Research On Estimation Methods Of Global Free-air Anomaly Base On Isostasy Theory

This dissertation focuses on the estimation methods of global free-air anomaly fromIsostasy theory. The main works are listed as follows:(1) The application of Airy system and spherical layer distribution in the construction of theEarth’s gravity filed model is studied, with the computational formulae presented in which theterrestrial and oceanic effects are taken into account. The isostatic potential model with CRUST2.0global crustal model is built, where the influences of compensation depth to both models areanalyzed.(2) Two application modes of CRUST2.0in the construction of isostatic potential modelare studied, which are visual topographic mode and seven layer compensation mode. Theformulae of visual topographic layer model, both for Airy system and spherical layer distribution,are deduced. The influences to the potential model construction with compensation depth indifferent models are also analyzed.(3) The effects, both in land and ocean area, of the first order radius derivation oftopographic and compensation potential are studied in detail. Based on the isostatic theory, theglobal free-air anomaly estimation model is constructed. The influence of compensation depth onthe gravity anomaly model precision is studied using SRTM topographic data.(4) The formulae of global free-air anomaly construction using visual layer model andseven layer compensation model are deduced, respectively.(5) Using EGM2008gravity anomaly of various resolutions as the quisa datum, the quisaaccuracy of the isostatic potential model and free-air gravity anomaly models with differentdatum is researched.(6) The precisions of computing height anomaly using EGM2008model, isostatic potentialmodel and combined model are studied, respectively, and then compared with each other.